biosphere atmosphere exchange 1) directly emitted ghgs co 2, ch 4, n 2 o 2) chemical sources of ghgs...
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Biosphere Atmosphere Exchange
1) Directly emitted GHGs
CO2, CH4, N2O2) Chemical sources of GHGs and SOA
BVOCs CO CO2
BVOC aerosol
3) Effects of biogenic emissions on O3, OH and NO3
NOx
BVOC H2CO
BVOC + O3 OH
•What are the magnitudes of these sources?
•How are they distributed, in time and space?
•How do they impact atmospheric chemistry & global greenhouse gases?
•What are the emissions of “natural systems”?
•What are the effects of management, e.g. fertilizer, timber forests?
Molecules:
CO2, CO, CH4, NO2, O3, H2CO, glyoxal
Aerosol properties
Satellite observations that will contribute
SOURCES OF ATMOSPHERIC METHANE
ANIMALS90
LANDFILLS50
GAS60
COAL40RICE
85
TERMITES25
WETLANDS180
BIOMASSBURNING20
GLOBAL METHANESOURCES (Tg CH4 yr-1)
Diffuse human-caused sources account for 365 in a total of 550 (70%). Agriculture accounts for 175 (30%)
1760 1780 1800 1820 1840 1860
020
0040
0060
0080
0010
000
Methane (ppb)
Alt
(m)
CH4 over North Dakota
Summer, 2000
(COBRA)
Growth of CH4 slowed dramatically after 1991. Will increases resume?
The vertical gradient over the Midwest is comparable to the gradient in the Amazon.
PRESENT-DAY GLOBAL BUDGET PRESENT-DAY GLOBAL BUDGET OF ATMOSPHERIC NOF ATMOSPHERIC N22O O
12 (9 – 16)SINK (Tg N yr-1)
Photolysis and oxidation in stratosphere
4 (3 – 5)ACCUMULATION (Tg N yr-1)
1 (1 – 2)Industrial
2 (1 – 3)Livestock
4 (1 – 15)Agricultural soils
8 (2 – 21)Anthropogenic
2 (1 – 4)Temperate soils
4 (3 – 6)Tropical soils
3 (1 - 5)Ocean
10 (5 – 16)Natural
18 (7 – 37)SOURCES (Tg N yr-1)
Although a closed budget can be constructed, uncertainties in sources are large! (N2O atm mass = 5.13 1018 kg x 3.1 10-7 x28/29 = 1535 Tg )
IPCC[2001]
2) Chemical Sources of GHGs and 2) Chemical Sources of GHGs and aerosolaerosol(BVOCs, (BVOCs, 1000’s of compounds)1000’s of compounds)
Isoprene (CIsoprene (C55HH88))
Monoterpenes (CMonoterpenes (C1010HH1616))
Oxygenated VOCOxygenated VOC
Sesquiterpenes (CSesquiterpenes (C1515HH2424))
OH O
CHOOH
Amount Known
C.Warneke et al., 2002
Agriculture produces a wide variety of highly reactive hydrocarbons, often in large quantities.
Concentrations and fluxes of oxygenated HCs over an alfalfa field in Colorado.
Methanol
Acetaldehyde
Acetone
Methanol
Acetaldehyde
Acetone
Mixi
ng ra
tio (p
pb)
Flux
(mg
m-2 h
r-1)
Secondary Organic Aerosol (SOA) Secondary Organic Aerosol (SOA) Production from biogenic VOC emissionsProduction from biogenic VOC emissions
IsopreneMono- and SesquiterpeneEmissions
Oxidation Reactions(OH, O3, NO3)
Nucleation (oxidation products)
Growth
Condensation on pre-existing aerosol
Nucleation(unlikely)
Graphic from M. Lunden
Goldstein and Galbally, ES&T 2007
Atmospheric VOC
SecondaryOrganic Aerosol
510-910 SOA Formation
310-720 Oxidation to CO/CO2``
175-375 Dry + Wet Deposition
130-270 Dry + Wet Deposition
~1300 Biogenic + Anthropogenic Global VOC Emissions
Units Tg C yr-1
50-200 Oxidation to VOC/CO/CO2
3) O3) O33, OH, NO, OH, NO33
Biogenic NOBiogenic NOxx emissions: OH, NO emissions: OH, NO33,, and Oand O33
BVOC BVOC HH22CO, aerosol oxidation?CO, aerosol oxidation?
OO33 + BVOC + BVOC OH + products OH + products
Cohen Group Meeting 31 August 2005
Partitioning of Global NOx Sources
SourceSource Tg N year Tg N year -1-1
Fuel ConsumptionFuel Consumption 2525
Biomass BurningBiomass Burning 66
Soil EmissionSoil Emission 99
LightningLightning ~10~10
TotalTotal ~50~50
Based on Jaegle et al. Faraday Discussions, 130, 407-423, DOI: 10.1039/b502128f, 2005
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aerosol formaldehydeacetaldehyde formic acidacetone acetic acidunidentified m/ z other 1other 2
OO
H O
Lee et al., JGR, 2006.
Terpenes and isoprene are source of H2CO
Terpenes + OTerpenes + O33 OH + OxProducts OH + OxProducts
Growing body of evidence that BVOC Growing body of evidence that BVOC emissions are a strong source of OH both emissions are a strong source of OH both within the forest canopy and above.within the forest canopy and above.
Goldstein et al. GRL and ACPGoldstein et al. GRL and ACPChemical OChemical O33 deposition depositionRapid Production of secondary VOC products Rapid Production of secondary VOC products
Helmig et al. ES&THelmig et al. ES&TSesquiterpene emissions are 20% of monoterpene emissions for Sesquiterpene emissions are 20% of monoterpene emissions for several pine speciesseveral pine species
Brune et al. JGR/ScBrune et al. JGR/ScieiencenceExcess OH observed in regions of high biogenic emissions including ground sites in Excess OH observed in regions of high biogenic emissions including ground sites in Alabama, Nashville and Michigan and from the aircraft. Alabama, Nashville and Michigan and from the aircraft.
Higher OH reactivity than accounted for by measured VOHigher OH reactivity than accounted for by measured VOC associated with biogenicsC associated with biogenics
Cohen Cohen ACPACPHNOHNO33 flux over a pine forest is upward implying 5-10 times more OH in the flux over a pine forest is upward implying 5-10 times more OH in the forest canopy than aboveforest canopy than above
MarMartinez (MPI-Mainz)tinez (MPI-Mainz)Excess OH correlated with isoprene over SurinamExcess OH correlated with isoprene over Surinam
Kulmala et al.Kulmala et al.Evidence in modeling and aerosol over forest in FinlandEvidence in modeling and aerosol over forest in Finland
0 6 12 18 24
0 6 12 18 240.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Time of Day
Summer (June-August) Blodgett Forest
Farmer and Cohen, in preparation
flux (ppb m s-1)
NO2∑PNs ∑ANs HNO3
mixing ratio (ppb)
0 6 12 18
-0.01
0.00
0.01
0 6 12 18
0 6 12 18
Summer—HNO3 flux
Calculated based on deposition velocity
Based on flux-gradient relationships
0.46 0.48 0.505
6
7
8
9
10
11
12
Hei
gh
t (m
)
HNO3 (ppb)
Chemistry
OH+NO2HNO3 OHcanopy = 3.1 x 107 molec∙cm-3
background OH ~5 x 106 molec∙cm-3
NO2 = 300ppt
Solve for OH needed to produce HNO3 that is identified as chemical.
OH = 3.1 x 107 molec∙cm-3
Residence time in the canopy is about 600 sec
-Di Carlo et al. [2004]Measured– Calculated OH LossInferred unmeasured reactive BVOCs.
-Kulmala et al., [2000] Aerosol growth Hyytiala Forest, FinlandFrom BVOC?
-Ciccioli et al. [1999] sesquiterpenes in leaf enclosures were not observed above the canopy – Burriana orange orchard, Spain.
MissionDirect GHG and NOx emissions
Industrial agriculture—target areas just after rain on recently fertilized fields, follow evolution over several days. Key goal verify/understand timing patterns so that can interpret satellite observations at one time of day.
Forest Emissions: Reactivity, Aerosol
Visit forests at that experience high T (maximum emissions). Bring new instruments capable of establishing links between BVOC emissions, OH and aerosol composition.
Conclusions
A focussed effort aimed at understanding:
• the timing and spatial patterns of biogenic emissions
• the propagation of these emissions as a result of exchange across the PBL and convection and
• the gas and aerosol chemistry of emissions
would likely provide exciting new scientific results.
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